The camera for the optical inspection in the bumper test system
News | Berghof Testing

Minimum cycle time, maximum flexibility

March 31, 2020

In recent years, Berghof Testing has repeatedly added new, innovative features to its concepts for bumper test systems and has thus become the market leader in the automated testing of bumpers. The latest and most complex bumper tester, which Berghof Testing has planned and implemented for one of the largest automotive suppliers, continues this successful tradition – because several new ideas from the Berghof Group's testing specialists are celebrating their premiere here. The result: The system now achieves new benchmarks in cycle time, flexibility and degree of automation.

Today, modern automotive bumpers have to perform significantly more functions than “just” absorbing impacts. Their primary task: They are central to the increasingly important topic of driver assistance systems. Modern vehicles are equipped with numerous, high-performance components that enable them to capture the entire environment of the vehicle accurately in fractions of a second.

Of course, this also poses completely new challenges for the developers of test systems for these assemblies. After all, the bumper manufacturers have to test all installed ultrasonic and radar sensors for their proper function before delivery to the respective automobile or commercial vehicle manufacturer. As more and more functions are added, an important feature of Berghof Testing's bumper test systems is increasingly becoming a major purchasing argument: in the field of sensor testing, they work with real-time signal evaluation, which significantly minimizes cycle times.

The installed cameras, hand free access and pedestrian protection systems as well as LED lighting elements also have to be tested by means of resistance and current measurement. This quickly shows how seriously a test system manufacturer takes the issue of flexibility: Berghof Testing's test systems, for example, are able to communicate with the components to be tested flexibly via all common bus systems such as Lin, Flexray or CAN – which is possible through the test software developed in-house.

In addition to these electrical test criteria, there are five important optical criteria: Does the bumper have the correct color? Are all mechanical components - i. e. attachments, clips or chrome parts – present and mounted in the correct position? And are these existing components the right ones, i. e. do they have the desired shape and color?

All these test criteria have to be checked exactly for all bumpers after assembly and before delivery to the respective vehicle manufacturer. In practice, complete photographic documentation has also proven to be a good way of proving the perfect condition of the assembly prior to transport if the customer complains about visual or technical defects after the bumpers have been delivered to his factory.

This procedure sounds complex and time-consuming, but with modern test systems, it works fully automated – as well as very fast with the latest bumper test bench from Berghof Testing, the Berghof Group's test system specialists. “Our latest bumper test system analyzes 55 optical inspection features in a cycle time of less than 45 seconds - and thus clearly undercuts the customer's specifications,” calculates Thomas Roth, Key Account Manager at Berghof Testing.

The secret: Berghof Testing has achieved here for the first time what all providers of such systems have failed to do so far. “Until now, the state of the art has been for a camera mounted on a robot arm to record all inspection features – and to do this, the robot has to come to a halt for each individual image and restart again after taking the picture. With our new plant, however, this process runs in a flow without these time-consuming interruptions. In addition, the movements of our robot are faster, because we rely on a particularly high-quality industrial robot that is less prone to failure. Of course, the safety of the personnel is still guaranteed: We use several safety laser scanners to check whether a person is in the hazard area before the robot starts,” continues Roth.

Additionally, the bumpers are fed to the test bench completely automatically with the help of a driverless transport system (DTS). The contacting between the device under test and the test cabin also works automatically. “We have developed a special transfer station with a standardized interface for this purpose. In this way, we ensure maximum flexibility of the system regarding the addition of new assemblies,” explains Roth. Another advantage: This transfer station is compatible with the specific assembly trolleys that OEM's often provide.

However, that is not all: To compensate for the manufacturing and assembly tolerances of the test carriages, the software works with robot workpiece coordinates. The system therefore automatically recognizes the different test carriages and compensates for tolerances by coordinate displacement. “This significantly reduces the time and effort involved in commissioning the system, because we only have to ‘teach-in’ each test vehicle type in the system only once,” explains Roth.

The seamless photographic documentation mentioned above also works completely automated with this system and is particularly convenient for the user: Each tested bumper is stored in the database with several high-resolution images, which are automatically labeled with the respective production number. Time-consuming searches in the event of a complaint are now a thing of the past.

As with each other Berghof test system, another particularly convenient feature is that the test interface is intuitive and easy to handle, – and that the system displays the OK/NOK results graphically and thus very clearly.

New variants of test specimens can also be added very quickly and easily directly via the user interface by simply creating new robot sequences and assigning them to the respective new test specimen variant – because Berghof's software is capable of processing variant-dependent robot sequences.

Not only because of this great flexibility and because of the well thought-out, convenient operating concept, the customer is highly satisfied with his new bumper test system. Even more importantly, the Berghof Testing system also optimally combines his main requirements of minimum cycle time and maximum automation – and, as already mentioned, the cycle time lies even significantly below the value required in the specification sheet.

Just as it should be for a market leader.